Adjusting The Upper Shaft Timing Belt; Adjusting The Rotary Hook Lubrication - Brother HE-800A Service Manual

4. ADJUSTMENT

4-22. Adjusting the upper shaft timing belt

4-23. Adjusting the rotary hook lubrication

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1. Remove the rubber cap (1).
2. Turn the adjusting screw (2) to adjust the lubrication amount.
* Adjust so that approximately 10 drops of oil are released when the sewing machine is run at a speed of 4,000
rpm for three cycles to sew about 114 stitches. Use Kraft paper (3) or similar to catch the oil drops. As a guide,
the optimum position can be obtained if the adjusting screw (2) is tightened as much as possible and then
loosened about two turns.
* Furthermore fine adjustments can then be made using the rotary hook joint screw (4).
* If the lubrication amount has been reduced, run the machine for 200 - 300 sewing cycles and then check it again.
Note: If lubrication stops, it will cause problems such as rotary hook seizure and thread breakages.
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1. Loosen the two bolts (1).
2. Use a spring gauge to push the notch in the
tension pulley plate (2) with a force of 98 N, and
then tighten the bolts (1).
* If you do not have a spring gauge, adjust the
tension so that the amount of belt deflection is
approximately 5 mm when a force of 5 N is
applied in the middle of the belt span between
timing pulley U (3) and the idle pulley (4) in the
place indicated by arrow A.
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HE-800A
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To oil tank
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